TiO_2/EDTA-rich carbon composites:Synthesis,characterization and visible-light-driven photocatalytic reduction of Cr(Ⅵ)

Ti02/EDTA-rich carbon composites(TiO_2/EDTA-RC) have been successfully synthesized via a low temperature carbonization process. TiO_2/EDTA-RC exhibits marked absorption of visible light and excellent photoreduction of Cr(Ⅵ) activity under visible light irradiation(λ420 nm). Due to the high carboxyl group content and strong coordination ability of EDTA, TiO_2-EDTA complex can be easily fabricated between EDTA incorporated in carbon sheet and titanol group on the surface of TiO_2. TiO_2-EDTA complexes on the surface of TiO_2/EDTA-RC, the LMCT complex, are responsible for the prominent photoreduction of Cr(Ⅵ) properties of Ti02/EDTA-RC under visible light irradiation. In addition, the unique structure ofTiO_2/EDTA-RC is also propitious to the visible-light photocatalytic reduction of Cr(Ⅵ).Carbon sheet of TiO_2/EDTA-RC acts as a supporter. TiO_2 nanoparticles and EDTA homogeneously disperse into the carbon sheet supporter and form the TiO_2-EDTA complexes, which can avoid the aggregation of TiO_2 nanoparticles in the aqueous solution and provide more photocatalytic reaction points for the reduction of Cr(Ⅵ).